低纬地区重力波活动的联合观测研究

Atomsphere behaviours at the low latitude are commonly recognized to have much more extraordinary properties than those at the middle and mid-high latitude region. And more special Gravity Wave (GW) behaviours could be observed there. It is quite meaningful to study the generating,propagating mechanism and their instability activities of GW. Considering with the geomorphology,tropical convection and ocean current factors, to further investigate the GW’s generating, propagating and breaking-dissipation mechanism at low latitude also have quite significant scientific meaning.. In this program, the multi-combined joint observation instruments will be used to study the GW behaviours(including lidar, meteor radar, digital ionosonde and all-sky airglow imager), which are located at Hainan and belonging to the newly brought scientific program - Meridian Space Weather Monitoring Project in China. Based on the above joint observation condition, the density pertubation, wind pertubation, Richardson number et al will be calculated. And moreover, nightly and seasonal variation distribution of GW activities, relationship between GW parameters, mechanics of Na layer inversion caused by GW and GW instabilies will be also studied depending on the joint observation. Depending on those data deprived from wind and temperature background, further studies that focusing on origining the GW source and the propagating mechanism also will be done. And by these multi-combined joint observations, it is quite convincing that the atmosphere GW behaviours at the mesospause of low latitude could be well investigated.

低纬地区相比于中纬度地区具有更加丰富的大气动力学特性，往往能够观测到更加特异的重力波行为。利用多种观测手段开展低纬地区中高层大气重力波的产生、传播机制及不稳定性的联合观测研究，并结合低纬地区地形、热带季风及对流，洋流因素等分析重力波的产生传播及破碎耗散机制。对深入了解低纬地区中层顶区大气动力学行为具有重要意义。.本项目将利用位于海南的子午工程多种观测设备（激光雷达、全天空气辉成像仪、流星雷达、数字测高仪等）的监测数据，提取重力波参数，并进一步计算密度扰动、风场扰动、Richardson 数等，通过多手段联合研究重力波活动的昼夜变化及季节变化、重力波的参数分布及相互关系，研究重力波破碎引起的钠层翻转机制及大气不稳定性规律，进而结合实测风场及温度数据，推断重力波波源位置，研究低纬地区上空重力波的产生机制。通过多手段联合观测，更加准确全面的描绘低纬地区中层顶区重力波活动的大气动力学过程。

低纬地区的重力波观测研究在中高层大气波动研究中具有特殊意义，海南地处青藏高原西南，同时拥有较低的地理纬度，其热带对流及季风特性可能在很大程度上影响着当地重力波的产生及传播过程，因而中国低纬地区上空的重力波活动观测情况很可能具有丰富的地区特殊性。.本项目通过以激光雷达为主的高空地基探测手段，对海南地区重力波行为进行长时间的观测积累研究，对所获得的观测数据进行分析，通过分离重力波参数，总结其季节变化规律，进而进一步初步推断出海南地区重力波波源位置。通过比较计算120E 的北京，武汉，海南三个地点的观测台站综合数据，计算出我国海南地区观测到的主要波源在位于120E 1000~1200km处，恰好位于青藏高原边缘处这一结论. 同时，结论表明在夏季的过程中，雷达观测的重力波扰动强度为全年最大，主要由青藏高原的地形因素的滤波效应和强对流共同作用，春秋两季的重力波主要受到来自青藏高原的地形波影响较弱，而冬季发现其活动强度仍然较强，具有独特的季节分布特性。与以往文献认为的我国冬季海南地区仍活跃的重力波波源可能来自中国南海的这一结论，本项目结合子午工程气辉仪观测到的数据并结合我国重力波冬季青藏高原---云南----海南传播路线的研究规律，形成海南地区冬季活跃的重力波波源更主要的是来自青藏高原的地形波传播的这一国内首创结论。同时，通过对比研究海南地区钠层密度特性。发现低纬地区重力波导致钠层结构发生变化。初步描绘了中高层大气中大尺度动力学循环与钠层变化之间的关系...